Features single and multiplayer co-op modes. The single-player portion of Portal 2 introduces a cast of dynamic new characters, a host of fresh puzzle elements, and a much larger set of devious test chambers. Players will explore never-before-seen areas of the Aperture Science Labs and be reunited with GLaDOS, the occasionally murderous computer companion who guided them through the original game. The game's two-player cooperative mode features its own entirely separate campaign with a unique story, test chambers, and two new player characters. This new mode forces players to reconsider everything they thought they knew about portals. Success will require them to not just act cooperatively, but to think cooperatively.

On the PS3 Portal 2 will be supported by Steamworks, a complete suite of game features and services including auto updates, community features, downloadable content, and more. Previously deployed on the PC and the Mac, Valve's Steamworks development platform will make it possible to deliver the higher level of service gamers have come to expect.